Manufacture of green bloom lubricating oils



Patented Aug. 18, 1936 UNITED STATES MANUFACTURE OF GREEN BLOOM LUBBICATWG OILS Donald K. Harger,

signor to Standard San Francisco, Calif ware Hermon Beach, Calm, aI-' Oil Comm! of California,

a corpora ion or Dela- No Drawing. Application January I, 1933-, Serial No. 650,740

,lilclaiml- (cries-1 This invention relates to a method at producin improved lubricating oils from overhead lubricating distillates, that is, distillates or stocks that have been subjected to distillation or the separation of the lubricating fraction from a base. More particularly, the invention relates to the production of improved lubricating oils from overhead stocks, the lubricating oils of this invention being characterized by the presence of a green bloom or fluorescence.

Overhead stocks are generally characterized in the fact that they exhibit a blue color or fluorescence when viewed by reflected light. Heretofore a method has been disclosed in United States patent to Hanna et al. Ila-1,566,000 patented Dec. 15, 1925, of imparting a rich green bloom or fluorescence to such lubricating oils. The process described in the aforesaid Letters Patent comprises the reduction of a cracking still residuum to the desired flash point and/or viscosity and the addition of such residuum to a lubricating oil distillate prepared in the ordinary manner. The mixture of cracking still residuum and lubricating oil distillate was then treated with acid, decolorizing agents, etc., for the production of a finished lubricating oil. This process, however, necessitated the use of a considerable quantity of a reduced bloom stock or cracking still residuum and the mixture of the bloom stock and the Inbricating oil stock was treated with strong acid. The use of such strong acid tended to destroy in part the active constituent, as far as green fluorescence is concerned, of the bloom stock. This prior process was also characterized by a lower 3 yield of lubricating oil on account of the presence of non-fluorescent components in the pressure still residuum which were very readily attacked by the strong acid used and formed a bulky sludge which retained considerable quantities of the lubricating oil.

In the present process, however, the residuum from petroleum cracking stills is treated with 60 per cent to 80 per cent sulfuric acid and such relatively weak acid treatment does not attack or reduce the green bloom-imparting components of the residuum. As a result, much higher yields of green bloom-imparting material may be obtained from a given volume of cracking still residuum.

Furthermore, the method of this invention contemplates the production of a concentrated bloom-imparting compound which is substantially free from waxes. Heretofore, a bloom-imparting material was substantially of the same viscosity as the lubricating oil in which such material was to be employed. The present bloom-imparting product is of a very materially higher viscosity and/or flash point, thereby facilitating the introduction of the bloom-imparting material into lubricating oils of very high viscosity. Moreover, in the process of the prior patent mentioned hereinabovc, the mixture of bloom-imparting material and lubricating oil stock was acid-treated and then neutralized and decolorizer, but in the proc- 5 ess of the present invention, after the concentrated bloom-imparting stock has been added to the lubricating stock it is not necessary to acidtreat the mixture but instead the mixture need only bev neutralized and/or decolorized. 10

It is an object of the present invention, therefore, to disclose and provide a simple and effective method of manufacturing lubricating oils which exhibit the desirable green bloom'or fluorescence. 15

Another object is to disclose and provide a method of producing a green bloom-imparting compound or material in concentrated form.

A further object is to disclose and provide a method of obtaining high yields of green bloom- 2 imparting material from cracking still residuums.

Another object is to disclose and provide a method of producing a concentrated green bloomimparting material which is substantially free from waxes and which does not deleteriously affect the characteristics of the finished lubricating oil but instead improves the characteristics of said oil.

7 These and other objects, uses and advantages 30 of this invention will become apparent to those skilled in the art from the following detailed description of a preferred method of producing the bloom-imparting stock and of a-mineral lubricating oil made from overhead distillates but having 35 the desirable green fluorescence or bloom when viewed by reflected light.

In carrying out the invention, the residuum from a petroleum. cracking still is preferably treated with sulfuric acid. It has been found that 40 strong acid is preferably not used as the strong acid tends to destroy in part the active bloom agent contained in the cracking still residuums. Treatment with 60 per cent to per cent sulfuric acid, however, does not impair or reduce 45 the yield of active blooming agent recovered from the residuum. As a matter of fact, recovered or black acid containing '70 per cent H2804r and obtained by hydrolysis of sulfuric acid sludge and partial concentration, may be satisfactorily used. When such black acid containing '70 percent H2804 is used, 1 pound per gallon of the residuum is suflicient.

The acid-treated residuum is then settled or 55 otherwise treated for the removal of the sludge formed during the acid treatment. This sludge is separately removed and the remaining acidtreated'tar is then subjected to vacuum distillation at a temperaturesumcient to remove sub- 60 of mercury gives best results.

stantlally all waxes and lighter components of the tar.

customarily, a reduction of the acid-treated tar with fire and steam at temperatures in excess of 600 F. under a vacuum of about 28 inches For example, if the reduction of the acid-treated tar is carried out at still temperatures of 660 F.-670 F. under about 28 inches of mercury vacuum, the residual product left in the still and containing the active green bloom-imparting components is a pitchlike substance having a melting point of about 140 F. to 150 F. The melting point may range from 125 F. to 155 F. r This bloom-imparting material is substantially free from waxes, the wax contained in the original pressure tar having been distilled oi! during the vacuum reduction,

although practically'none of the active blooming agent was carried overhead during the distillation.

By the use of the relatively weak acid and the use of high temperatures during the reduction of the pressure tar as described hereinabove, the resulting product contains the active green bloom or green fluorescence-imparting bodies in high concentration and a very high yield of such active green bloom-imparting bodies is obtained from a unit weight of the original cracking still residuu m. Moreover, certain of the prior art products were not completely oil soluble and their use resulted in-the introduction of insoluble-sludge residues or required'additional extraction steps. The products of this invention, however, are completely oil soluble.

The concentrated bloom stock produced as above described may then be added to any acidtreated lubricating oil in desired amounts for the purpose of imparting the desirable green bloom or fluorescence thereto. Because of the high content of active bloom-imparting ingredients in the bloom stock, and complete solubility of the stock in oil, it is only necessary to add a very small amount of such stock to the lubricating oil. In practice, from 0.2 per cent to 4.0 per cent of such-bloom stock by weight need be added to the lubricating oil. The addition is most conveniently made by reducing a the bloom stock to liquid form before adding the same to the lubricating oil. It may be here mentioned that the concentrated bloom stock made as described 'hereinabove is stable under all ordinary circumstances. The bloom stock may be maintained at a temperature of 250 F. for prolonged periods of timewithout. impairing its bloom-imparting characteristics.

A mixture of lubricating oil such as an acid treated lubricating distillate, and the bloom stock,.is preferably neutralized and decolorized. The neutralization may be accomplished by washing with alkali, thisstep being followed by decolorization with a solid decolorant such'as clay or other adsorbent. If desired, both the neutralization and decolorization may be accomplished by a solid adsorbent. The neutralizing and decolorizing steps need not be described in detail here as they'are well known in the art.

The oils resulting from the process described hereinabove have certaindesirable characteristics when compared with the oils treated in accordance with the process of the prior patent mentioned hereinabove. In the following table, two finished. lubricating oils are compared-oil A having been made in accordance with Patent No.

1,566,000, whereas oil B has been made in accordance with the process of this invention:

It is to be noticed that it was necessary to add 4.25 per cent of the tar processed in accordance with the prior patent to obtain a fluorescence similar to that obtained bythe use of only 1.25 per cent of the concentrated bloom stock made in accordance with this invention.' 'I'hisreduction in the amount of bloom stock added to the overhead distillate influencesthe viscosity figures of the resulting lubricating oil. Itis seen, for example, that the viscosity of oil B, made in accordance with this process, is materially higher and better than that of oil A. Attention is also called to the fact that the Conradson'carbon content of the'product of this invention is appreciably smaller. A lower Sligh number is also ob-,

tained. The increase in viscosity and the lowering in the Conradson carbon and Sligh number is a characteristic distinction of all comparisons made between this invention and the prior method.

In the specific illustration given hereinabove. the organic acid is the same in both oils but in' the majority of cases the organic acid of lubrieating oils made in accordance with his process is lower than the organic acidity of oils made in accordance with the prior. method. H 1 .1

Moreover, the oils made in accordance with this invention show substantially no wax present. An empirical test which'has been used in making this wax determination consists in blowing the finished oils with air for 30 minutes in abath held at 32 F. The thickness of the "was te produced is measured. The oils are then permitted to stand for 16 hours at 32 F. and the wax foam? then measured. A sample of the foam is then examined microscopically and graded as to the number of wax crystals per unit volume. It has been found that the amount of foam is correlated to the wax content. Light and medium lubricating oils made from the concentrated bloom stock in accordance with this invention show substantially no foam, whereas all grades of oil made in accordance with the prior process show appreciable thicknesses of "wax foam" and a relatively high number of wax crystals upon microscopic examination.

In the production oflubricating oils by the process of Patent No. 1,566,000, the pressure still residuum mixed with the lubricating distillate is subjected to the action of strong acid. The presence of the pressure still residuum in the mixture causes an abnormally high acid refining loss. In the present process this high loss is avoided by acid treating the pressure still residuum and the lubricating oil distillate separately. As a result, the total acid requirements are from 7 to 10 per cent lower to produce a given quality of finished oil than those required in the prior process. In all instances the fluorescent effect produced by the concentrated bloom stock is much superior to that obtained by the use of. the residuum treated as described in the aforesaid Letters Patent.

It will be obvious to those skilled in the art that the present invention provides an efficacious, economical and readily adaptable method of producing a concentrated bloom stock and lubricating oils characterized by a green fluorescence which are of a materially higher grade than those produced heretofore.

Although a specific mode of operation has been described in detail in order to specifically define the invention, it is to be understood that numerous changes, modifications and variations may be made without departing from the scope of the invention as expressed in the appended claims.

All such changes and modifications as would occur to those skilled in the art and come within the scope of the appended claims are embraced thereby.

I claim:

1. A method of refining and imparting a green fluorescence to lubricating oils, which comprises treating residuum from petroleum cracking stills with an acid containing 60 to per cent H2804, separating and removing the resulting sludge, subjecting the tar remaining from such acid treatment to a vacuum distillation at a temperature suflicient to remove substantially all waxes and lighter components of said tar while retaining bloom-imparting constituents to form a pitchlike stock, then adding the resulting concentrated bloom-imparting stock to acid treated lubricating oil in amounts of from 0.2 per cent to 4.0 per cent by weight, and finally neutralizing and decolorizing the mixture.

2. A method of refining and imparting a green fluorescence to lubricating oils, which comprises treating residuum from petroleum cracking stills with an acid containing 60 to 80 per cent H2804, separating and removing the resulting sludge, subjecting the tar remaining from such acid treatment to a vacuum distillation at a temperature suflicient to remove substantially all waxes and lighter components 0! said tar while retaining bloom-imparting constituents to form a concentrated pitch-like stock, and then adding the resulting concentrated bloom-imparting stock to acid treated lubricating oil in amounts of from 0.2 per cent to 4.0 per cent by weight.

3. A method of refining and imparting a green fluorescence to lubricating oils, which comprises treating residuum from petroleum cracking stills with an acid containing 60 to 80 per cent H2804, separating and removing the resulting sludge, subjecting the tar remaining from such acid treatment to a vacuum distillation at a temperature sufiicient to remove substantially all waxes and lighter components of said tar while retaining bloom-imparting constituents, then adding the resulting concentrated bloom-imparting stock to a lubricating distillate not requiring chemical refinement in amounts of from 0.2 per cent to 4.0 per cent by weight, and then decolorizlng the mixture.

4. A method of refining and imparting a green fluorescence to lubricating oils, which comprises treating residuum irom petroleum cracking stills with an acid containing 60 to 80 per cent H2804, separating and removing the resulting sludge, subjecting the tar remaining from such acid treatment to a vacuum distillation at a temperature above 600 F. to remove substantially all waxes and lighter components or said tar while retaining bloom-imparting constituents to form a concentrated pitch-like stock, and then adding the resulting concentrated bloom-imparting stock cating oils by solution to acid treated lubricating oil, and finally neutralizing and decolorizing the mixture of. lubricating oil stock and bloom stock.

5. A method of producing a concentrated bloom-imparting stock, which comprises treating residuum from petroleum cracking stills with an acid containing 60 to 80 per cent H2804, separating and removing the resulting sludge, and subjecting the tar remaining from such acid treatment to a vacuum distillation at a temperature suiiicient to remove substantially all waxes and lighter components of said tar while retaining bloom-imparting constituents.

6. A method of refining and imparting a green fluorescence to lubricating oils, which comprises treating residuum from petroleum cracking stills with an acid containing 60% to 80% H2804, separating and removing the resulting sludge, subjecting the tar remaining from such acid treatment to a vacuum distillation at a temperature sufiicient to remove substantially all waxes and lighter components of said tar while retaining bloom-imparting constituents, and then adding the resulting concentrated bloom-imparting stock to acid treated lubricating oil.

7. A method of refining and imparting a green fluorescence to lubricating oils, which comprises: treating residuum from petroleum cracking stills with an acid containing 60% to 80% H2804, separating and removing the resulting sludge, subjecting the tar remaining from such acid treatment to a vacuum distillation at a temperature suflicient to remove substantially all waxes and lighter components of said tar while retaining green bloom-imparting constituents in the form oi an oil soluble, pitch-like stock having a melting point of between F. and F., and then adding the resulting concentrated bloom-imparting stock to lubricating oil.

8. A method of the character stated which comprises treating residuum from petroleum cracking stills with an acid containing 60% to 80% H2804, separating and removing the resulting sludge, and subjecting the tar remaining from such treatment to a vacuum distillation at a temperature above'about 600 F., said temperature being sufilcient to remove substantially all waxes and lighter components of said tar while retaining bloom-imparting constituents in the form of an oil soluble, concentrated, pitch-like stock having a melting point of between about 125 F. and 155 F.

9. As an article of manufacture, a pitch-like compound resulting from the vacuum distillation or petroleum cracking still residuum, said pitchlike compound being completely soluble in petroleum oils, having a. melting point of between 125 F. and 155 F. and being substantially free from wax, said pitch-like compound being capable of imparting green fluorescence to petroleum lubricating oils by solution therein.

10. As an article of manufacture, a pitch-like compound resulting from the vacuum distillation of petroleum cracking still residuum, said pitchlike compound being completely soluble in petroleum oils, having a melting point oi. between 125 F. and 155 F. and being substantially free from wax, said pitch-like compound being capable oi! imparting green fluorescence to petroleum lubritherein and being capable or increasing the viscosity of oils in which it is dissolved without increasing the Conradson carbon content.

DONALD K. EARGER. 

